A Study On The Collection And Processing For The Deeper Layer's Seismic Data In The North Of Songliao Basin

The deeper layer's seismic prospecting lays foundation to look for a deep resources in the whole basin depth. The deeper layer's seismic prospecting in this paper means the job carried on under Quantou group in the North of Songliao Basin. While making use of the seismic data to make a geology explanation and research currently, usaually exist the problems that structure explaining is many and identifying of the structure and the rock loop is low. The factors that influences quality of deep work have ground geology conditions, underground geology conditions, collecting techniques, data processing techniques and construction quality, the recogniza- tion to the former seismic information and the level of explaining and so on.As a result it demand to carry on a various research work to want to acquire the quality good deeper layer's seismic data. To the region of bad surface conditions and weak reflect layer in deeper layer,it`s even difficult to obtain data of the high quality. Aiming at the characteristics of the weak seismic wave energy, low resolution, low Signal-to-Noise, this paper studied the surface geology conditions of the North of the Songliao basin, deeper layer's seismic geology conditions, systematically analyzed the quality of the deep layer's seismic informations existed(Chaoyanggou—Shanzhan,Zhaozhou—Changwu,Gulong,Gulongnanbu,Duiqingshan,Shuangcheng,Renminzhen- Qinggang,Taikang-Gulong,SongⅠBig section,SongⅡBig section,G-66 Big section,SongⅣBig section,SongⅤBig section),the techniques of data collecting and data processing, detailedly researched the reflect ability of the deep layer in the North of Songliao basin and logically gave a general method to acquire seismic data in the North of Songliao basin, especially the data collecting and processing to the weak reflecting in deeper layer and dipper reflect information.In the research of the deep layer's seismic data quality, carry on the quality variety analysis of the T3,T4,T5 reflect layers, including the discussions to the deep reflect information quality of five big sections and eight regions; In the study of the deep reflect quality, aiming at Chaoyanggou-Sanzhan,Zhaozhou-Changwu regions etc., discuss the sections influenced by the surface variety,horizontal variety of the reflect layers,the reflect characteristics of the reflect layers and distanceattenuation etc., and carry on a contrast of the reflect energy among T3,T4,T5 reflect layers.In the research of the data collect method, detailedly illuminate the design thoughts and methods of the deep layer's seismic data collect technique; also discuss the methods of detector combination, seismic source combination, consociation combination; Elaborate on the principle and the method of collect parameter choice, such as channel distance, offset and the biggest source-receiver distance; theoretically discuss the disperse effect of the same reflect point under many reflect layers, this has certain function to the design of fold.Following discussed the reflect ability of the deeper layer in the North of Songliao Basin. The research to the error between the depth of exploration well and the depth of diagram made by seismic informations in the L1,L2,L3,L4 layers demonstrate that the reflect wave isn`t caused by a certain underground obvious interface, but caused by the comprehensive effect produced by two pieces close different seism toward the incident wave. In the calculation of the reflect coefficient of the transition layers, give the calculation formula of the reflect coefficient of the transition layers, and make use of this formula to carry on a calculation for the reflect coefficient of the 50 meters and 100 meters depth transition layers, know that the different transition layer thickness has different reflect coefficient. Make use of the circle sources to study the reflect ability of the deeper layers, compare the data using circle sources experiments to give a support to the design of the data collect of the deep informations. This kind of method is more dependable and easier than the fold method, can improve the traditional design method of the data collect with the surface distribution of the reflect coefficient.At the aspect of the data processing, for better carrying on the deep explore, reasonably give the processing flow in the different regions, the different surface geology conditions. According to the detailed discussion, suggest that Shuangcheng-Duiqingshan processing flow is the basic flow. Aiming at the noisy problem caused by the big incline angle and the noise with bigger angles,put forward two kinds of data processing techniques: The technique of the big incline angle processing and the technique of the incline angle filter. The incline angle filter is a kind of two dimensions filter, also called the fan filter or apparent velocity filter. Adopt a new kind of two fan filter method---DDF incline angle filter with difference formula recursion. This method makes use of the limited difference formulacalculation to carry out two dimensions incline angle filter with the recursion calculation in the (t, x) field. It saves the positive and negative Fourier transformation in the traditional method, not only saving the memory but also improving the calculation speed and accuracy greatly. In the handling the solid example, mainly depict the improvement of the data processing of the Fanyshen1-Fangshen2 line.The deep layer's seicmic prospecting becomes a system, including the instruction function and the complement function of the deep deposition characteristics, deep regional geology, deep structure geology and the geophysics work etc.to the seismic explore. The deep geology problem has established the integrity theories, so the deep layer's seicmic prospecting needs to build up the integrity theories and perfect work methods to give a guide to the seicmic prospecting. This paper just makes initial research to the deep layer's seicmic prospecting method to give a basic support to the deep layer's seicmic prospecting in the future.This paper does researches to the quality of the former seismic information, the data collect in the field, the ground geology, underground geology condition and the data processing method. The result demonstrates that the former deep work has obtained much useful information, and the T4 reflect layer information is so good that it gives a general recognization to the basement; In the meantime accumulate experience in the data collect, including the parameter of the observation system, the combination way etc..The data processing also obtains some experience.T3 in the Songliao basin is a weak reflect layer.The surface of basement rises and falls greatly and the ground condition is complicated, which make the influence of different degree to the deep exploration work.